This invention relates to electrochemical cells. More particularly, it is concerned with primary electrochemical cells having an oxidizable active anode material, a cathode current collector, and an electrolytic solution comprising a reducible liquid cathode material and an electrolyte solute dissolved therein.
A particularly effective class of primary electrochemical cells which employs soluble or liquid cathode materials, as opposed to the more conventional solid cathodes, has undergone rapid development in recent years. In these cells the active cathode material is usually a fluid solvent for an electrolyte solute which provides conductivity. The active anode of the cell is usually lithium or other highly electropositive metal. During discharge the solvent is electrochemically reduced on a cathode current collector.
A wide variety of materials have been employed to make up cathode current collectors. Improved cathode current collectors and methods of making them are described in U.S. Pat. No. 4,219,443 to Keith A. Klinedinst and Francis G. Murphy. Improved high rate performance characteristics have been obtained with lithium/oxyhalide electrochemical cells employing a cathode current collector fabricated of a composite of carbon black particles with platinum particles supported thereon. These cells are disclosed and claimed in U.S. Pat. No. 4,272,593 to Keith A. Klinedinst. Another class of materials which have been employed as catalysts in cathode current collectors for reducing an oxyhalide solvent are metal phthalocyanines. Cells employing these materials are described in U.S. Pat. No. 4,252,875 to Hanumanthiya V. Venkatasetty. Although improved high rate performance characteristics have been obtained with cells employing the foregoing catalytic materials in cathode current collectors, they may not be suitable for certain applications because of relatively high cost or limited stability in the presence of other materials of the cell.